Extent and Rate of Reaction

Question 1

What are the 4 principles that can explain the behaviour of ideal gases?

Answer 1

• A gas is made of lots of molecules so small compared to the distances between them therefore size is ignored
• In constant, rapid, straight line motion, colliding frequently
• Collisions are elastic, no kinetic energy is lost/ gained during collisions
• The average kinetic energies are proportional to temperatures

Question 2

What is speed proportional and inversely proportional to?

Answer 2

• Proportional to temperature
• Inversely proportional to molecular mass

Question 3

What is Collision Frequency proportional to?

Answer 3

• To temp at constant volume
• To pressure at constant volume

Question 4

Why does viscosity decrease with temperature?

Answer 4

• The particles have more kinetic energy - less resistance to flow more easily pourable

Question 5

How do ions move through solvent?

Answer 5

• Through application of potential difference
• Ion channels - move

Question 6

How does conductance increase and decrease?

Answer 6

• increases with number of ions channels present and cross section of medium
• decreases with length

Question 7

What is diffusion?

Answer 7

• Force that represents spontaneous tendency to disperse - increases disorder

Question 8

What are the different examples of potential energy?

Answer 8

• Electric
• Temperature
• Concentration
• Gradient - energy of molecule due to position

Question 9

What is Kinetic energy

Answer 9

• Energy distributed amongst its rotational (about an axis), translational (one place to another) and vibrational (motion of 1 atom in relation to another) motion (movement)

Question 10

What is the rate equal to?

Answer 10

• Number of collisions per unit time x fraction with sufficient energy x appropriate orientation

Question 11

What are further factors that affect the rate?

Answer 11

• Temperature
• Catalysts
• Concentration
• Physical state - Same state

Question 12

What is the rate equation?

Answer 12

• Rate = k[A]^n[B]^m
  k = kinetic rate constant

Question 13

How does temperature affect the rate?

Answer 13

• Increase with temp
• Straight line with natural log of k (Arrhenius)

Question 14

How does a catalyst affect the rate? - 3 ways

Answer 14

• Activate the reactant
• Stabilise Transition State
• Different reaction mechanism

Question 15

How do you measure the rate?

Answer 15

• Gaseous - increase in pressure
• Spectrophotometric - measurement of radiation in UV
• Conductivity - production of H+ ions - pH